Engine starter



Nov. 21, 1950 A. M. MADLE ENGINE STARTER Filed May 10, 1945 Patented Nov. 21, 1 950 ENGINE STARTER Alain M. Madl, Milwaukee, Wis., assignor to Briggs & Stratton Corporation, Milwaukee, Wis., a corporation of Delaware Application May 10, 1945, Serial No. 593,023 2 Claims. (Cl. 74-7) This invention relates to engine starters of the so-called automatic type having a pinion automatically propelled into and out of mesh with the ring gear of an engine to be started by relative rotation between screw threaded parts carried by the pinion and an actuator for the pinion.

The object of the present invention resides in the provision of an engine starter of the character described wherein the actuator for the pinion is rotatable and slidable along the power shaft and wherein driving torque is transmitted from the power shaft to the actuator by means of a novel splined connection therebetween embodying endwise resiliency for cushioning of axial thrust on the actuator during operation of the starter.

With this and other objects in view which will appear as the description proceeds, this invention resides in the novel construction, combination and arrangement of parts substantially as hereinafter described and more particularly defined by the appended claims, it being understood that such changes in the precise embodiment of the hereindisclosed invention may be made as come within the scope of the claims.

The accompanying drawing illustrates one complete example of the physical embodiment of the invention constructed according to the best mode so far devised for the practical application of the principles thereof, and in which:

Figure 1 is a side elevational view of the starter of this invention with .parts broken away and shown in section to better illustrate details of construction and showing the pinion of the starter in its inoperative retracted position;

Figure 2 is a view similar to Figure 1 but illus trating the pinion in an operative projected position which it occupies during cranking of the engine;

Figure 3 is an end view of the starter taken along the lines 3--3 of Figure 1; and

Figure 4 is a cross sectional View through Figure 1 taken on the plane of the line 44.

Referring now more particularly to the accompanying drawing in which like numerals indicate like parts, the numeral 5 designates the power shaft of a starting motor 6 upon which the starter assembly, indicated generally by the numeral 1, is mounted.

The starter assembly comprises a tube 8 telescoped over the power shaft 5 and drivingly fixed thereto by means of a set screw 9 passing through the hub of a collar l0, mounted upon the outer free extremity of the tube, for engagement with the power shaft 5. While not specifically illustrated, it is to be understood that the set screw 9 has its extremity entering into a well in the side of the power shaft so as to secure the tube and collar thereto for rotation with the power shaft and so that the tube, in effect, forms a part of the power shaft.

The customary pinion H is slidably and rotatably received on the inner end of the sleeve 8 and has an internally threaded sleeve l2 projecting therefrom toward the collar to receive an externally screw threaded actuator I 3 slidable upon the tube 8 between the pinion and the collar l0.

Hence, it will be apparent that relative rotation between the pinion and actuator in one direction effects propulsion of the pinion along the tube 8 from its inoperative retracted position illustrated in Figure 1 to an operative pro- ,iected position illustratedin Figure 2 and defined by engagement of the forward face of the pinion with a pinion stop l4 secured to the inner end of the tube 8; and that relative rotation between the pinion and actuator in the opposite direction upon starting of the engine effects retraction of the pinion to its Figure 1 position.

As in all engine starters of this type, interference with forward propulsion of the pinion toward mesh with the engine ring gear I 5 such as occurs either upon improper meshing of the gears or upon the pinion engagingits stop I4, establishes a driving connection between the actuator and pinion by which the actuator 13 is subjected to rearward end thrust tending to move the actuator axially toward the collar I0.

In the present design, this end thrust is absorbed by cushioning means in the form of a stack of cupped spring washers I B on the tube 8 positioned between axially spaced flanges I1 and is on the actuator and collar respectively. The flanges l1 and I8 are substantially normal to the axis of the power shaft.

The spring washers l6 maintain the actuator separated from the collar III with the forward end of the actuator received within the pinion sleeve engaging against an annular abutment on the tube 8. The abutment 8 is readily provided by a spring ring 20 sprung into an annular groove 2| in the exterior surface of the tube ahead of the actuator.

The flange I! on the actuator is also provided with a substantially cylindrical skirt 22 extending rearwardly therefrom over th spring washers and the flange l8 of the collar to substantially enclose the washers, The skirt 22 and the flange 11 thus form, in effect, a cup open at its end adjacent to the collar ID to receive the spring washers, and the skirt has a slot 23 extending longitudinally inwardly in from the open end of the cup to receive a lug 24 projecting substantially radially outwardly from the periphery of the flange ill on the collar 10 to provide a splined driving connection between the collar and actuator so that "the actuator rotates with the power shaft and the tube '8.

The depth of the slot 23 is such as to allow axial movement of the actuator toward the collar 10 such as occurs as the result of end thrust on the actuator during cranking of the engine, as illustrated in Figure 2, and which thrust is cushioned and absorbed by the stack of spring washers l6 confined between the abutments I! and i8.

The action of the spring washers it is such as to afiord a degree of both endwise and torsional resilienc for the pinion during operation of the'starter so as vto relieve the starter of excessive shocks 'such as when the pinion suddenly pic'ksup the load of theen'gine or upon improper meshing of the gears.

Uponretraction of the pinion to its fully inoperative position illustrated in Figure 1, an abutine t-25 on the interior of the pinion sleeve adjacent to its juncture with the pinion engages against a squared end 26 on one of the actuator threads to limit pinion retraction and thereby preclude any wedging action which might otherwise'result.

From the foregoing description taken in connection with the accompanying drawing, it will be'readily apparent to those skilled in the art that the splined connection between th power shaft and the actuator for the pinion is effected in a most simple manner and'additi'onally provides for enclosing the resilient cushioning means which absorbs axial thrust of the pinion and its actuator during operation of the starter.

Iclaim:

1. In an engine starter of the type having a pinion propelled "along a power shaft into and out of mesh with an engine gear by relative rotation between screw threaded parts on the pinion and 'an actuator for the pinion rotatable and slidable along the power shaft, a driving connection between the power shaft and actuator, comprising: a collar fixed on th power shaft; axially spaced abutments on the actuator and collar; compression spring means reacting between said abutments for holding the actuator and collar axially spaced apart and for yieldingly resisting axial movement of the actuator toward the collar ,4 to thereby provide cushioning against axial thrust of the actuator during operation of the starter; a skirt on one of said abutments encircling said spring means and the other abutment; a lug on said other abutment engaged in a longitudinal slot in the skirt so as to provide a splined driving connection between the collar and actuator permitting a degree of axial movement of the actuator relative to the *collar; and a stop on the 'power shaft at the side of the actuator remote from said spring means engaged by the actuator to limit axial motion thereof under the influence of said spring means, said stop comprising a spring ring sprung into an annular groove in the powershaft.

2. In an engine starter of the type having a pinion propelled along a power shaft into and out of mesh with an engine gear by relative rotation between screw threaded parts on the pinion and an actuator for the pinion rotatable and slidable along the power shaft, a driving connection between the power shaft and actuator, comprising: a collar fixed on the power shaft; means on the actuator and collar providing axially spaced flanges substantially normal to the axis of the power shaft; cushioning means confined between said flanges to yieldingly resist axial motion of the actuator toward the collar and thereby "absorb axial thrust of the actuator developed during operation of the starter; a'skirt on the flange carried by the actuator encircling said cushioning means and the collar flange; and a lug on the collar flange engaging in a longitudinal slot in the skirt to provide a splined driving connection between the actuator and collar permitting a degree of axial motion of the actuator relative to the collar.

ALAIN M. MADLlil.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS France Aug. 31, 1936 

